1. Field of the Invention
This invention relates to a rotary flow control valve having use in a multiple cycle liquid treatment apparatus, and more particularly to an improved rotary flow control valve that automatically starts and stops different cycles of the liquid treatment apparatus.
Water softening apparatus using ion exchange resin particles must be regularly regenerated with brine in order to restore or maintain the water hardness removing capacity of the resin particles. The flow control valve for such apparatus must accurately control the volume and velocity of liquid flowing through the resin particles in the treatment tank and in the brining system during each of four or more cycles. Automatic water softening apparatus used in single family residences has to be capable of operating under a wide range of pressure, flow, and hardness conditions, as are typically found in such residences. Prior flow control valves, usable under such a wide range of conditions, were often unduly complicated and difficult to service because they had a large number of moving parts. Also, such prior valves were not capable of being used with different types of liquid treatment equipment, for instance filters which require high flow rates during their backwash cycle.
2. Description of Related Art Including Information Disclosed under Secs. 1.97-1.99
The rotary flow control valve of this invention is an improvement on the liquid flow control valve set forth in U.S. Pat. No. 4,136,032, entitled, Liquid Treatment Apparatus, issued Jan. 23, 1979. Valves manufactured in accordance with the teaching of that patent have served well. However, the need to make improvements therein has been recognized. It is desirable for such a flow control valve to provide a precise number of flow paths, each for a predetermined time period, in a cyclical pattern without need for precise calibration or adjustments. Further, it is desirable that the valve be assembled from a minimum number of components, which components are readily assembled without the need for precise adjustments during or following assembly. The desired improvements relate to the manufacturing of components of the valve, the assembly of the components of the valve and related components of the liquid treatment apparatus, and also to the operation of the valve.